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Bulletin No.: PIP4112S

Published date: 03/12/2018

Preliminary Information

PIP4112S Normal Characteristic – Sag Or Hesitation On Acceleration

Models

*Excludes vehicles equipped with Diesel Engines

Supersession Statement:

This PI was superseded to update Model Years and Recommendation/Instructions. Please discard PIP4112R.

Condition / Concern

Some customers may comment on a sag or hesitation when accelerating under the following conditions:

When coasting at low speeds of less than 15 miles per hour with a closed throttle and then aggressively applying the throttle. Examples of this maneuver include a rolling stop or a lane change maneuver. In this type of maneuver, even though the accelerator is applied aggressively, the throttle blade is opened slowly for up to 0.7 seconds to help minimize drive-line lash and clunking. Also in a vehicle equipped with an automatic transmission when making a hard, complete stop with a closed throttle, immediately followed by an aggressive throttle opening the transmission down-shifts may not be completed by the time the throttle is opened.

As a result approximately 0.5 seconds of ″zero″ torque may be commanded to allow the shift to first gear to occur.

Customers may also comment on a sag or hesitation while cruising at highway speeds and then aggressively increasing the throttle forcing a down-shift.

This type of driving maneuver may result in approximately 0.5 seconds of ″zero″ torque being commanded to allow the down-shift to complete.

Recommendations / Instructions

All of the above conditions are a result of Torque Management and all of these conditions should be considered normal and no repairs should be attempted.

Please follow this diagnostic or repair process thoroughly and complete each step.

If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

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